Related Questions

In convection heat transfer from hot flue gases to water tube, even though flow may be turbulent, a laminar flow region (boundary layer of film) exists close to the tube. The heat transfer through this film takes place by
A Convection
B Radiation
C Conduction
D Both convection and conduction
If the digit in the unit's place of a two-digit number is halved and the digit in the ten's place is doubled, the number thus obtained is equal to the number obtained by interchanging the digits. Which of the following is definitely true ?
A Sum of the digits is a two-digit number
B Digit in the unit's place is half of the digit in the ten's place
C Digit in the unit's place and the ten's place are equal
D Digit in the unit's place is twice the digit in the ten's place
Air is to be heated by condensing steam. Two heat exchangers are available (i) a shell and tube heat exchanger and (ii) a finned tube heat exchanger. Tube side heat transfer area are equal in both the cases. The recommended arrangement is
A Finned tube heat exchanger with air inside and steam outside
B Finned tube heat exchanger with air outside and steam inside
C Shell and tube heat exchanger with air inside tubes and steam on shell side
D Shell and tube heat exchanger with air on shell side and steam inside tubes
The scales form in heat exchanges after a period of operation and provide additional resistance to heat transfer with some heat transfer coefficient . The reciprocal of this scale heat transfer coefficient is called .
A scaling factor
B forming factor
C resisting factor
D fouling factor
In a shell and tube heat exchanger for a given heat transfer surface area, smaller diameter tubes are favoured as compared to larger diameter ones ; because the smaller diameter tubes
A Are easier to clean
B Are less prone to fouling
C Can be fitted into a smaller shell diameter hence the cost of the heat exchanger would be less
D None of these
For the same heat load and mass flow rate in the tube side of a shell and tube heat exchanger, one may use multipass on the tube side, because it
A Decreases the pressure drop
B Decreases the outlet temperature of cooling medium
C Increases the overall heat transfer coefficient
D None of these
If the radius of cylinder is halved and height is doubled , then what will be the curved surface area?
A Increase by 1
B The same
C Double
D Triple
if the radious of cylinder is halved and height is doubled, then what will be the curved surface area
A increase by one
B the same
C double
D triple
If th radius of cylinder is halved and height is doubled, then what will be the curved surface area?
A icrease by 1
B the same
C double
D triple
If the radius of cylinderis halved and height is doubled, then what will be the curved surface area?
A increase by 1
B the same
C double
D triple

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